Ship Type Explained: What Each AIS Category Means
In this article 6 sections
Switch a vessel label on MarineRadar to Type instead of Name, and every triangle on the map turns into a word: Cargo, Tanker, Fishing, Passenger. That field is called ship type, and it comes from a two-digit code buried in the same AIS broadcast that puts the dot on the map in the first place. Most people only ever see the word the app prints, never the number behind it, and that’s usually fine. It stops being fine the moment a 400-metre container ship and a research vessel both show up labelled “Other,” or a coast guard cutter reads “Law Enforcement” instead of “Military,” and you want to know whether the tracker made a mistake or the ship did.
What the Ship Type Field Actually Is
Ship type is not something a tracking app invents from a ship’s silhouette or its name. It’s a field the vessel itself broadcasts, set once by whoever registered the AIS transponder and rarely touched again afterward, following a standard the International Telecommunication Union laid out that gives every type a two-digit number from 00 to 99. That number travels over VHF radio to the coastal receivers and satellites that pick up AIS everywhere, and it’s exactly what MarineRadar reads when you switch a vessel label on the map over to Type instead of Name.
Two digits carry the whole system. The first sorts a ship into one of ten broad families; the second, where it’s filled in, adds detail about what the ship is carrying.
The Ten AIS Category Groups
Here is the first digit, grouped the way the standard actually breaks it down.
| Code range | Category | What you’ll actually see |
|---|---|---|
| 00 | Not available | Default value. The transponder never had a type entered, or hasn’t sent one yet. |
| 20-29 | Wing-in-ground craft | Vanishingly rare outside a handful of Russian and Chinese hovercraft-style vessels. |
| 30 | Fishing | Trawlers, longliners, purse seiners. |
| 31-32 | Towing | Tugboats under tow, including the long, awkward tows that barely fit a single AIS position report. |
| 33-35 | Dredging, diving, military ops | Working vessels and naval activity, not warships specifically. |
| 36-37 | Sailing, pleasure craft | Yachts and sailboats, Class B transponders more often than not. |
| 40-49 | High-speed craft | Fast ferries and hydrofoils running well above normal cruising speed. |
| 50-59 | Special craft | Pilot boats, search and rescue, tugs, port tenders, law enforcement. |
| 60-69 | Passenger | Everything from a harbour ferry to an ocean-going cruise ship. |
| 70-79 | Cargo | Container ships, bulk carriers, general cargo, the bulk of what AIS tracks. |
| 80-89 | Tanker | Oil, chemical and gas tankers, kept separate from dry cargo. |
| 90-99 | Other | Anything that doesn’t fit cleanly elsewhere, a genuine catch-all. |
Most people searching for ship type only care about five or six of those rows. The rest exist for completeness.
Cargo and Tanker, the Two Biggest Groups
Codes 70 through 89 cover the ships that make up most live-map traffic, and shipping splits them into two families rather than one. Cargo and tanker look similar from a distance, both large, both slow, both running scheduled routes. The industry still treats them as separate businesses, and the AIS code reflects that:
- Separate owners and operators, almost never the same shipping line
- Separate ports, since a grain terminal and an oil terminal share almost nothing
- Separate safety rules, driven by what happens if the cargo spills
Inside the cargo range sit container ships, bulk carriers and general cargo vessels; the differences between those five common hull types matter more to someone chartering a ship than to someone watching one go by. A tanker, by contrast, is built almost entirely around tank space and piping, and MarineRadar’s own tanker guide covers how to follow an individual oil tanker live once you’ve spotted one by its type label.
Passenger Ships and Pleasure Craft
Codes 60 to 69 catch everything built around seats and cabins rather than cargo holds: cruise liners, car ferries, harbour water taxis. A 350-metre cruise ship and a 20-metre island ferry share the same first digit because both exist to move people, not freight. If you specifically want to follow a cruise ship live, the passenger code is the fastest way to tell it apart from a cargo ship crossing the same strait at the same time of day.
A private yacht is not one of these.
Pleasure craft sit in a different family entirely, code 37, grouped with sailing vessels rather than with passenger ships, and that distinction trips people up constantly because both groups obviously carry people rather than freight. Most yacht owners fit the cheaper, lower-power Class B transponder rather than the commercial-grade Class A unit a ferry is required to carry, which is one more reason the two categories end up looking similar on a map and behaving nothing alike on paper.
Fishing, Towing and the Working Boats
Fishing gets its own single code, rather than a range, and the three after it belong to vessels doing physical work on the water instead of moving cargo or people from one port to another:
- 30, Fishing: trawlers, longliners, purse seiners
- 31-32, Towing: a tug pulling a barge, or a long, awkward tow that barely fits a single position report
- 33, Dredging and underwater operations
A tug pulling a barge and a tug nosing a container ship into berth can carry the same type code but behave completely differently on the map, one crawling across open water for days, the other making tight circles in a harbour for twenty minutes.
Military, Law Enforcement and the Vessels That Go Dark
Code 35 covers military operations, but it’s one of the least reliable labels in the whole system, because most warships simply don’t transmit AIS at all during anything resembling an operation. Naval vessels carry transponders, and NATO ships often broadcast one in peacetime for collision avoidance, but a ship on patrol has every reason to go dark and none to advertise its position to anyone with a browser.
A dark warship hasn’t malfunctioned; crews switch the transponder off on purpose.
What a tracker can and can’t show about warships is really a question about transmission, not about the type code itself; the code only matters for the fraction of military traffic that chooses to broadcast. Law enforcement (55) and search and rescue (51) are far more consistent, mostly because coast guard and rescue agencies want to be seen, not hidden, so a cutter running a routine patrol typically shows its correct type the whole time, which is more than you can say for half the fishing fleet.
Why the Second Digit Matters for Cargo and Tankers
Codes 70 through 89 don’t stop at the first digit.
The second digit, where it’s filled in, flags whether the vessel is carrying hazardous or polluting cargo and how severe that hazard is rated. A plain 70 or 80 means no hazard information was specified.
Moving up through the range gets more specific about the category of dangerous goods aboard, which matters enormously to a port authority deciding where a ship can berth and very little to someone just confirming a ship is a tanker rather than a bulk carrier. Plenty of commercial ships never bother filling it in at all, even when carrying cargo that would technically call for it.
The subcategory is useful when it’s there. It’s absent often enough that nobody should rely on it being there.
Step 1: Turn On Vessel Labels on MarineRadar
Open the map’s main options sheet from the home screen and tap Map options, the same bottom sheet used to switch between standard, satellite and nautical styles. Scroll to the Display on Map card and confirm Vessels is switched on; labels can’t show anything if the layer underneath them is off.
Step 2: Find the Vessel Label Display Card
Once vessels are showing, a new card called Vessel Label Display appears directly beneath Display on Map. This is the setting that controls what text, if any, shows next to each ship icon.
Step 3: Switch the Label to Type
Tap the Vessel Labels switch to expand a row of five chips: Vessel Name, MMSI, IMO, Type and Speed. Choose Type, and every visible ship on the map relabels itself immediately using the same AIS classification described above. This is the fastest way to scan a crowded strait or anchorage for, say, every tanker among two dozen cargo ships, without opening a single vessel card.
Where Ship Type Gets It Wrong
A ship’s type is set once, usually at installation, and it can simply be wrong from day one. A transponder installer picks the closest matching code from a dropdown, and a 90-metre general cargo ship can end up coded as 79 rather than 70, or a research vessel ends up filed under 90, Other, because nothing in the list quite matches what it does. None of this is AIS malfunctioning. It’s a human entering a value once and nobody revisiting it for the life of the ship.
Reflagging and resale make this worse. A ship can change owners, change names, change operators, and the type code from the previous owner’s installation carries over untouched unless someone specifically updates it. Names get fixed eventually because they’re visible and embarrassing when wrong. Type codes sit quietly in the background and often never get corrected at all.
Ship Type Is Not Cargo Content
The single most common confusion about ship type is assuming it describes what’s on board. It doesn’t, and it was never designed to. A label reading Cargo tells you the hull is built to carry freight. It says nothing about whether that freight is machinery, grain, or forty-foot containers stacked eight high, because AIS has no field for cargo manifest at all. That information lives in the shipping line’s own booking system, not in the public radio broadcast a live tracker reads.
Tanker works the same way in reverse. Code 80 tells you the hull is built around tank space. It does not tell you whether those tanks hold crude oil, refined fuel, vegetable oil or liquified gas, only that the vessel is the kind of ship that carries bulk liquid rather than solid cargo or passengers. For anyone who actually needs to know what a specific vessel is carrying, the type code is a starting point, not an answer.
Conclusion
Ship type is one broadcast field doing a surprisingly large amount of work: ten rough categories, a second digit for hazard detail where it’s filled in, and decades of individual installers making a one-time judgement call about which code fits their vessel.
It’s reliable enough to sort a busy anchorage into fishing vessels and cargo ships at a glance, and unreliable enough that a wrong or missing label shouldn’t surprise anyone.
Treat the word on the map as a strong hint about what you’re looking at, and confirm it against the vessel’s name or MMSI when it actually matters. The occasional “Other” stops being confusing once you know it’s exactly what it looks like: a ship that never quite fit the list.
FAQs
What does ship type mean on AIS?
It’s a two-digit code the vessel’s own transponder broadcasts, sorting it into one of roughly ten categories such as cargo, tanker, passenger or fishing. A live tracker reads that code and shows the matching word next to the ship on the map.
Who sets a ship's type code?
Whoever installs the AIS transponder, typically at the shipyard. It’s almost never revisited after that.
Why does my ship tracker show 'Other' for some ships?
Codes 90 through 99 are a genuine catch-all for vessels that don’t fit cleanly into cargo, tanker, passenger, fishing or the other defined groups. Research vessels, unusual workboats and some naval auxiliaries often land there simply because nothing on the standard list matches what they actually do, and whoever filled in the transponder’s details picked the closest thing available rather than leave the field blank.
Can ship type tell you what a ship is carrying?
No. It tells you the category of vessel, cargo ship versus tanker versus passenger ship, not the contents of its holds or tanks. AIS has no field for cargo manifest at all; that data sits in the shipping line’s own booking system, not in the public broadcast a live tracker reads.
What AIS code is a fishing boat?
Code 30.
Is a pleasure craft the same as a passenger ship on AIS?
No. Passenger ships sit in the 60-69 range, and pleasure craft get a separate code, 37, grouped with sailing vessels instead. Both groups carry people rather than freight, which is exactly why the split confuses so many people the first time they notice it.
Why do warships rarely show a military type code in practice?
Most naval vessels switch AIS off during anything resembling an operation, so the code barely matters in practice.
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